This invention is an improvement over a prior invention also assigned to the present assignee and now U.S. Pat. No. 4,188,784 which issued Feb. 19, 1980.
The aforementioned patent discloses an articulating type of exhaust connector. Many of the same components are disclosed in the above-identified patent such as: a seating surface formed at the outlet end of a manifold or the like; a header carrying a seal member thereon to engage the seating surface and to direct exhaust gases from the manifold to the header in a substantially leak-resistant manner as accomplished by engagement between the seal and the seating surface. The patent exhaust connector also has a flange means spaced away from the seating surface and connected to the header. Coil-like springs engage the flange to bias the flange, header and the seal against the seating surface. The coil springs encircle bolt fasteners which extend from the manifold, through an aperture in the flange means and terminate in an enlarged head portion which engages one end of the coil spring. With this arrangement, the flange, seal and header are biased by the force of the coil springs toward the seating surface.
The exhaust connector of the aforementioned patent has worked quite satisfactorily on front-wheel drive Chrysler vehicles since about 1978. However, the coil springs are subject to aging causing a decrease in biasing capacity due primarily to exposure to the relatively high heat resulting from exhaust gases in the engine manifold. In addition, the springs are exposed on the exterior of the connector where they encircle the bolt-like fasteners holding the connector together. Thus, the springs are subject to damage from rocks or the like which may be thrown up from the road during operation of the vehicle.
The subject improved connector utilizes many of the same components as found in the aforementioned connector, but provides an improved spring means to maintain sealing contact between the seal member and the seating surface formed by the manifold or the like. Specifically, the improved connector utilizes a spring backing plate instead of a flange attached to the header. The backing plate has a central aperture encircling the header. Radially outwardly placed apertures are provided through which fastener means extend, the head portion of which engages the spring back-up plate and secures it to the manfold. The header itself has radially outwardly extending flange means to form an axial stop or seat on one side for the seal member carried on the header. The other side of the header flange forms an axial stop or surface which engages an inner diameter portion of a Belleville or washer type spring means. The outer diameter portion of the spring means engages the spring back-up plate at a location inwardly from the bolt fasteners. Further, the spring back-up plate includes normally extending tabs adjacent the aperture therethrough so that the back-up plate can be drawn toward the manifold a predetermined spacing distance which defines the desired resultant distortion of the spring as determined by the assembled spacing between the spring back-up plate and the flange means on the header.
The improved connector thus utilizes a conically shaped Belleville washer-type spring to provide the seating bias between the seal and the seating surface to ensure a relatively leak-proof articulated connection between the manifold and the header. The Belleville spring is better protected than the previous coil springs since it is located inward with respect to the bolt fasteners and is also relatively compact in dimension. Also, the relatively large surface area of the conically shaped Belleville spring tends to disperse or dissipate heat rapidly to the atmosphere. The minimal contact between the inner diameter edge of the spring and the header provides a relatively limited heat path to the spring from the header. The outer diameter edge of the Belleville spring rests against the spring back-up plate which, with its central aperture surrounding the header, but not contacting the header, does not readily pick up heat from the manifold or header. This is contrasted to the connector shown in the aforementioned patent in which the header flange which forms an axial stop for both the seal and the spring plate provides a substantial surface to transfer heat from the header to the spring. Also, as previously mentioned, the coil-type spring of the earlier patent connector is relatively exposed to damage from a number of sources, such as objects thrown up from the highway.
The use of a Belleville washer-type spring for biasing is not in and of itself new as evidenced by an earlier patent briefly described hereinafter. The connector shown in FIG. 2 of U.S. Pat. No. 3,798,903 utilized Belleville type springs labelled 76 and 94. A seal member 90 engages a flared portion 82 of a header 80. An axial limiter is provided by a flange 84 member secured to a stationary support 72 by bolt 86. The Belleville spring 94 acts directly on seal 90 and against a member 70. The second Belleville spring 76 bears against the stationary support member 72 and the intermediate member 70 to bias the whole assembly against the manifold member 24 and gasket 78.
The assembly described in the previous paragraph teaches that Belleville springs have previously been utilized in association with exhaust connectors. Important differences between the U.S. Pat. No. 3,798,903 device and the subject connector should be noted. Generally, it is unclear at best from a careful reading of the patent, whether the connector assembly is intended to accommodate any substantial articulation between exhaust components. Rather, it appears that the purpose of the connector is simply to isolate the exhaust components from a ceramic exhaust manifold. Specifically, the Belleville washer 76 is not utilized in association with the articulated connector, but instead merely seats a stationary base member 70 away from a support member 72 and against a manifold 24. The other Belleville washer 94 is utilized in a location directly between stationary member 70 and the seal itself. This arrangement has many and substantial disadvantages as opposed to the subject articulated connector. While the Belleville spring 94 of the U.S. Pat. No. 3l,798,903 is well protected, it is by necessity limited in size and strength and it is also utilized in a manner subjecting it to substantial transfer of heat from exhaust gases. It is believed that a Belleville spring utilized as shown would, of necessity, have to be formed of relatively expensive high temperature materials or otherwise the spring would soon lose its resiliency and the sealing relationship of the connector would be defeated. Also, the limits of travel of the spring from an unstressed position to a stressed position appear to be unusually small.
Therefore, an object of the present invention is to provide an improved articulated type connector between exhaust system components and providing a seal carried by one exhaust component to be seated against a surface of another exhaust component by means of the bias of a conical shaped washer-type spring, the inner diameter edge portion of which only engages an exhaust component thus decreasing the heat transfer surface area of the spring.
Another object and advantage of the subject articulated connector is the provision of a seal carried by one exhaust component which is biased against the seating surface of a second exhaust component by means of a conical washer-type spring, the outer diameter edge portion of which engages a spring back-up plate having a central aperture encircling, but not engaging the header so that the spring back-up plate does not transfer a significant amount of heat from the exhaust gases to the spring.
Another object and advantage of the subject exhaust connector is the provision of an exhaust connector in which a seal is biased against one exhaust component, a conically shaped washer-type spring is engaged by edge contact only with an exhaust component and the other edge portion of the spring engages a plate not significantly contacting an exhaust component so that a minimal surface contact for heat transfer is made between the spring and a relatively hot exhaust components.
A final object and advantage of the subject exhaust connector in which a seal member is biased against a seating surface of one exhaust component arises from the use of a conically shaped washer-type spring between one exhaust component which supports the seal and a spring back-up plate which is adjustably fastened to a second exhaust component by means of bolt fasteners, the desired spacing between the back-up plate and the exhaust component establishing spring distortion and being determined by tab means on the spring back-up plate to specifically space the plate to thereby bias the conically shaped spring a desired amount.
Other objects and advantages of the subject invention of this application will be more readily apparent after a reading of the following Detailed Description of a Preferred Embodiment which are disclosed in the drawings of this application described as follows.